1. Field of the Invention
This invention relates to the improvement of a cleaning roller for an intermediate transfer member and a cleaning method therefor, and particularly to the improvement of a cleaning member used in contact with an intermediate transfer member of a reproducing apparatus which operates for transferring a toner image formed on a toner image forming member to the intermediate transfer member and further transferring the toner image to a subsequent transfer material from the intermediate transfer member for fixaction and of a cleaning method therefor.
2. Description of the Prior Art
An intermediate transfer member of a reproducing apparatus has an elastic material layer such as silicone rubber and fluororubber on the surface as a transfer layer, and a cleaning method of such intermediate transfer member by means of a blade or a heat resisting cloth is not enough to obtain a satisfactory effect of cleaning unlike that for a toner image forming member and a fixation press roller with the surface which is high in hardness and formed smoothly, and is liable to damage the transfer surface of the intermediate transfer member. A cleaning method for the intermediate transfer member which utilizes the property that a adhering strength of the toner to metal is more powerful than that to the transfer layer of silicone rubber or the like is known according to U.S. Pat. No. 3,649,992. The method comprises cleaning the intermediate transfer member by rotating a metallic cylinder in contact with the intermediate transfer member. However, it is not satisfactory to obtain a sufficient cleaning effect and has a problem of wearing down the transfer surface in most cases. More specifically, since the toner remains a little on an intermediate transfer layer, a cleaning action of the metallic cylinder does not deteriorate within a very short time. Still, however, as a toner adhesion quantity to the metallic cylinder increases, the toner adhesion quantity does not become uniform normally in the direction of a rotation axis of the metallic cylinder and thus a ruggedness is produced thereon. Therefore an adhesion of the metallic cylinder to the surface of the intermediate transfer member deteriorates, and thus the cleaning action becomes dull in consequence.
It is also known that a metallic cylinder is used as a cleaning roller for fixation press roller which brings a recording paper into pressure contact with the intermediate transfer member according to Japanese Utility Model Laid-Open No. 91546/1975. These methods utilize the property that the adhering strength of the toner to metal is more powerful than that to silicone rubber, fluororubber, fluororesin or the like provided on the surface of the intermediate transfer member and fixation press roller at a specific temperature range. However, if the cleaning roller is a mere metallic cylinder or metallic roller, the surface is too hard to fit on the intermediate transfer member or the fixation press roller, and a thermal capacity is too large to allow the temperature to rise easily, thus causing a problem on obtaining a satisfactory cleaning effect.
On the other hand, there is known a reproducing apparatus which forms a toner image and transfers it onto a recording paper at the first revolution of a toner image forming member by means of a magnetic brush device and then cleans the toner image forming member at the second revolution by means of the common magnetic brush. However, the method by means of the magnetic brush device commonly working for development and cleaning is available for an electrostatic reproducing apparatus using a two-component developer consisting of a toner and a magnetic carrier, but the toner image forming member tends to be stained by toner and fogged accordingly.